New Molecular Technique Solves Mysterious Transplant Deaths

Action Points

Explain to interested patients that many molecular methods of identifying the cause of disease are now available, but they all rely on knowing the sequence of the pathogen involved.

Note that this study outlines a method that can identify a mystery pathogen even if nothing is known about it.

NEW YORK, Feb. 6 -- When three transplant recipients died of a febrile illness within weeks of getting their new organs, their doctors were puzzled. None of the usual tests found a cause.

But a new molecular technique -- dubbed unbiased high-throughput sequencing -- was able to identify the pathogen, a hitherto-unknown arenavirus, according to Ian Lipkin, M.D., of Columbia University, and colleagues.

The new technique used tissue from the transplanted organs, all from the same donor, to generate a library of more than 100,000 RNA sequence fragments, Dr. Lipkin and colleagues reported online in the New England Journal of Medicine.

Fragments of known sequences were subtracted and the researchers were able to piece together the previously unknown arenavirus from what was left, the researchers said.

Finally, infection of the victims was confirmed using conventional tools, including culture, electron microscopy, and immunohistochemical and serologic tests, the researchers said.

Polymerase chain reaction tests derived from the newly discovered sequence showed the virus was in the kidneys, liver, blood, and cerebrospinal fluid of the recipients.

Also, the researchers said, immunohistochemical tests showed antigens to the virus in the transplanted organs and antibodies were found in the serum of the donor.

The detection method has potential in any situation where a disease outbreak is caused by an unknown agent, Dr. Lipkin said. "It's like astronomy, where you're able to see all the stars that are present," he said.

It may also be useful in basic research, where a pathogen is suspected of causing a type of disease but with few clues about the nature of the organism, he added.

In contrast, he said, conventional tools used to identify pathogens can only find those that are already known, he said.

The researchers reported that three women in Australia had received a liver and the kidneys from a 57-year-old donor who had died of a cerebral hemorrhage 10 days after returning to Australia from a visit to the former Yugoslavia.

The immediate post-transplant course was normal, Dr. Lipkin and colleagues said, but all three developed febrile illnesses with varying degrees of encephalopathy. They died four to six weeks after the surgery.

The novel arenavirus is related to lymphocytic choriomeningitis virus, which usually has only mild symptoms in otherwise healthy people, Dr. Lipkin and colleagues said, although it has been implicated in some cases of aseptic meningitis.

In recent years, molecular techniques have been used to identify a range of pathogens, said Richard Whitley, M.D., of the University of Alabama at Birmingham.

But such techniques fail "when the agents in question are truly novel or sufficiently distant in sequence from related agents that they confound hybridization," Dr. Whitley said in accompanying perspective article.

The technique described by Dr. Lipkin and colleagues should solve that problem, he said, and allow the identification of a range of new pathogens. That, in turn, should allow novel therapeutic and preventive approaches, he said.

He pointed out that "it is ideal for applications in which unknown bacteria, fungi, parasites, or viruses may be involved."

As examples, he noted that as many as 40% of patients with altered mentation, fever, and inflammation of the central nervous system never receive a diagnosis that establishes the cause of their illness. Additionally, acute respiratory tract infections account for nearly two million deaths annually in the United States, with an agent identified in only 30% to 60% of cases. Similarly, in the United States alone, 5,000 deaths each year are attributed to foodborne infections of unknown cause.

Accessibility Statement

At MedPage Today, we are committed to ensuring that individuals with disabilities can access all of the content offered by MedPage Today through our website and other properties. If you are having trouble accessing www.medpagetoday.com, MedPageToday's mobile apps, please email legal@ziffdavis.com for assistance. Please put "ADA Inquiry" in the subject line of your email.